Boiler and method of making same

ABSTRACT

A boiler, in particular a hot-water or central-heating boiler, is made with elements defining on one side a component part of a fire duct and on the other side a component part of a water duct. This permits the elements to be cast without using sand cores, thus allowing more scope in design and permitting the use of light metals for higher heat transfer efficiency.

United States Patent [1 1 Giesen 51 Oct. 29, 1974 BOILER AND METHOD OF MAKING SAME [75] Inventor: Gerardus Johannes Giesen, Tegelen,

Netherlands [73] Assignee: Blondu A.G., Vaduz, Liechtenstein [22] Filed: June 19, 1972 [21] Appl. No.: 264,299

[52] U.S. Cl 122/225 R, 29/157.4, 29/5275, 29/DlG. 48

[51] Int. Cl. F22b 7/00, B2ld 53/00 [58] Field of Search 29/l57.4, 527.5, DIG. 48, 29/527.6; 122/225 R [56] References Cited UNITED STATES PATENTS 655,457 8/1900 Savery 29/l57.4 X 2,042,036 5/1936 Buckley 122/225 R 2,454,866 ll/l948 Gallaher 122/225 R FOREIGN PATENTS OR APPLICATIONS 90l,l4l 7/l962 Great Britain 29/lS7.4

Primary Examiner-C. W. Lanham Assistant Examiner-D. C. Reiley, lll Attorney, Agent, or Firm-Silverman & Cass [5 7 ABSTRACT A boiler, in particular a hot-water or central-heating boiler, is made with elements defining on one side a component part of a fire duct and on the other side a component part of a water duct. This permits the elements to be cast without using sand cores, thus allowing more scope in design and permitting the use of light metals for higher heat transfer efficiency.

7 Claims, 2 Drawing Figures BOILER AND METHOD OF MAKING SAME This invention relates to a boiler composed of separately cast elements, in particular a hot water or central heating boiler, having at least one fire duct and at least one water duct. The invention also relates to a novel method of making such a boiler.

In known boilers the elements are made of cast iron or steel by casting, using cores for forming the ducts. Not only does this impose limitations in the design of the various ducts, because the cores used must be removable, but also sand residues from the core casting process may be left in the water ducts, which cannot be removed.

It is an object of the invention to eliminate this drawback according to the invention, there is provided a method of making a boiler having at least one fire duct and at least one water duct, which comprises casting elements formed to define on one side a component part of a water duct and on the other side a component part of a fire duct, and interconnecting said elements by welding. The method according to the invention has the advantage that the water and fire ducts, without affecting the production price, may have any possible form, perfectly suited to heat transfer through the walls separating fire and water ducts. For instance, the walls of a water duct are so accessible that it is possible to realize a degree of roughness with a view to the desired heat exchange by means of any desired finishing operation.

The manufacture of such a boiler through casting without cores is particularly suitable for light metal construction, such as of an aluminium alloy. Since such material makes for much more efficient heat exchange through the wall between a fire duct and a water duct than is the case with cast iron or steel, a higher rate of water circulation can be applied, which in combination with a chosen surface condition of the water tubes can be utilized for minimizing the weight and sizes of the boiler.

Corrosion in the fire and water ducts is avoided if an aluminium alloy is employed and welding stresses will be minimal. Since furthermore the surface roughness of the walls of the water duct can be realized as desired, it can be avoided that water drops in rough places lag behind in relation to the circulation so that steam formation and burning are avoided.

One embodiment of the invention will be described, by way of example, with reference to the accompanying drawing. In said drawings,

FIG. 1 is an exploded view of a part of the boiler and FIG. 2 is a cross-sectional view on the line llll in FIG. 1.

Referring to the drawings, there is shown a detail of a central heating boiler with two water ducts on either side of a fire duct. The boiler is composed of four elements 1, 2, 3 and 4 which are united to form a boiler body through a plurality of welds (see FIG. 2).

Outer wall elements 1 and 4 are provided at the sides opposite the centre of the boiler with baffle sections 5, 6 which, in a composite boiler together with opposite baffie sections 5, 6 on boiler elements 2 and 3 form baffles in the two water ducts confined between boiler elements 1 and 2, 3 and 4, respectively.

The fire duct portion bounded by boiler elements 2 and 3 is provided with projections 8 reaching from the respective fire duct walls towards each other, e. g. in the form of truncated pyramids. These projections serve for increasing the heat transfer from the hot gases traversing the fire duct to the walls of the fire duct.

Cast inte rally with element 2 is a stub 7 extending across the ire duct, which stub, in an assembled boiler, provides a water connection between the two water ducts disposed on either side of the central fire duct. The free end of stub 7 is accommodated, in an assembled boiler, in a ring 11 formed at element 3 and embracing the end of stub 7. When the boiler is assembled the end of stub 7 is welded to ring 11 so as to avoid water leakage to the fire duct.

In a number of places of one or both of the outer elements 1, 4 may be formed inlet stub, possibly provided with threading 9.

I claim:

1. In a method for making a boiler having at least one fire duct and at least one water duct, the improvement comprising the steps of: forming elements of the boiler by casting, the boiler comprising at least four elements, first and second of said elements being configured to define on one side of each thereof a se ment of a water duct and on the other side a segment 0 a fire duct, joining said first and second elements together by welding to define therebetween said fire duct, the third and fourth elements being configured to define on one side of each thereof a segment of a water duct, joining by welding each of said third and fourth elements respectively to opposite sides of said first and second elements joined together to form said fire duct thereby to form a water duct on each side of said fire duct.

2. A method according to claim 1, which comprises casting the elements without cores.

3. A method according to claim 1, which comprises casting the elements from an aluminium alloy.

4. In a boiler composed of separate elements and having at least one fire duct and at least one water duct, the improvement comprising said boiler including at least four cast elements, the first and second of the elements being configured to define on one side of each thereof a segment of a fire duct and on the other side a segment of a water duct, said first and second elements being joined together and interconnected by welding to form said fire duct therebetween, and the third and fourth elements being configured to define on one side of each thereof a segment of a water duct, and said third and fourth elements being joined to opposite sides of said first and second elements joined together to form said fire duct and being connected respectively by welding to each side of said fire duct such that a grater duct is formed thereby on each side of said fire uct.

5. A boiler according to claim 4, wherein the elements consist of an aluminium alloy.

6. A method according to claim 1 including the steps of: forming a hollow open ended stub in one of the said two joined elements, said stub extending across said fire duct; forming a stub receiving opening in the other of the said two joined elements, said stub being re ceived in said opening to form a cross water duct between said water ducts formed on opposite sides of said fire duct; and securing said stub in said opening by welding.

7. A boiler according to claim 4 wherein one of the said two joined elements has a hollow open ended stub extending from the fire duct forming side thereof, and the other of the said two joined elements has a stub receiving opening therein which is sized and arranged to receive and have secured therein the distal end of said stub thereby to form a cross water duct across said fire duct between said water ducts on opposite sides of said fire duct. 

1. In a method for making a boiler having at least one fire duct and at least one water duct, the improvement comprising the steps of: forming elements of the boiler by casting, the boiler comprising at least four elements, first and second of said elements being configured to define on one side of each thereof a segment of a water duct and on the other side a segment of a fire duct, joining said first and second elements together by welding to define therebetween said fire duct, the third and fourth elements being configured to define on one side of each thereof a segment of a water duct, joining by welding each of said third and fourth elements respectively to opposite sides of said first and second elements joined together to form said fire duct thereby to form a water duct on each side of said fire duct.
 2. A method according to claim 1, which comprises casting the elements without cores.
 3. A method according to claim 1, which comprises casting the elements from an aluminium alloy.
 4. In a boiler composed of separate elements and having at least one fire duct and at least one water duct, the improvement comprising said boiler including at least four cast elements, the first and second of the elements being configured to define on one side of each thereof a segment of a fire duct and on the other side a segment of a water duct, said first and second elements being joined together and interconnected by welding to form said fire duct therebetween, and the third and fourth elements being configured to define on one side of each thereof a segment of a water duct, and said third and fourth elements being joined to opposite sides of said first and second elements joined together to form said fire duct and being connected respectively by welding to each side of said fire duct such that a water duct is formed thereby on each side of said fire duct.
 5. A boiler according to claim 4, wherein the elements consist of an aluminium alloy.
 6. A method according to claim 1 including the steps of: forming a hollow open ended stub in one of the said two joined elements, said stub extending across said fire duct; forming a stub receiving opening in the other of the said two joined elements, said stub being received in said opening to form a cross water duct between said water ducts formed on opposite sides of said fire duct; and securing said stub in said opening by welding.
 7. A boiler according to claim 4 wherein one of the said two joined elements has a hollow open ended stub extending from the fire duct forming side thereof, and the other of the said two joined elements has a stub receiving opening therein which is sized and arranged to receive and have secured therein the distal end of said stub thereby to form a cross water duct across said fire duct between said water ducts on opposite sides of said fire duct. 